1. Field of the Invention
The present invention relates to a sample analyzer, to which a measuring unit is detachably connected.
2. Description of the Related Art
The followings are prior-art devices related to the present invention.
(1) A biological fluid analyzing device for analyzing biological fluid constituents by measuring optical characteristics of a biological fluid sample, the device having a sample receiving port and a pump connection port, and comprising at least one sample treatment chamber, an optical measurement chamber and, optionally, a waste liquid reservoir provided between the sample receiving port and the pump connection port and communicating with one another through flow channels (see, for example, U.S. Pat. No. 5,681,529).(2) A disposable measuring element comprising: a measurement channel with at least one optical or electrochemical sensor incorporated therein; a first port provided in association with one of opposite ends of the measurement channel for connection to an analyzer; a second port provided in association with the other end of the measurement channel for connection to a sample-taking part; and a common sealing element provided for the first and second ports and having first, second and third positions; wherein the opposite ends of the measurement channel are closed when the sealing element is at the first position; wherein the one end of the measurement channel is connected to the first port and the other end of the measurement channel is connected to a collection tank provided in the measuring element for collecting a liquid drained from the measurement channel when the sealing element is at the second position; wherein the one end of the measurement channel is connected to a buffer tank provided in the measuring element and the other end of the measurement channel is connected to the second port when the sealing element is at the third position (see, for example, U.S. Pat. No. 5,228,350).
In the prior art, the measurement unit (the biological fluid analyzing device or the measuring element) is connected to a sample analyzer, so that only the measurement unit is contaminated with the sample. Therefore, the sample analyzer is kept clean without contamination.
However, if the prior art sample analyzer fails to detect a signal from the sample after the sample is introduced therein, the sample is uselessly consumed. Particularly where the sample is a blood sample or the like taken from a baby or an infant, the amount of the sample is very small. Therefore, the useless consumption of the sample should be avoided.